The present invention relates to a baby carriage. More particularly, the invention relates to a baby carriage each of the four wheels at the front and rear of which can be freely swung to steer the carriage.
A conventional baby carriage can be moved back and forth with four wheels. Since the baby carriage has a simple constitution wherein the wheels are merely rotatably attached to both ends of axles secured to the front and rear of the carriage, the efficiency of steering of the carriage is very low. This is a problem.
To solve this problem, another conventional baby carriage having front wheels swingable in the manner of swivel casters has been proposed. The baby carriage has four wheels, which are the right and left front wheels a and right and left rear wheels b as shown in FIG. 8. Only the front wheels a attached to the front legs of the baby carriage are mutually independently supported by swivel mechanisms 8, as shown in FIG. 10, so that the front wheels can be not only rotated about the axes thereof but also freely swung rightward and leftward to steer the baby carriage. The rear wheels b are attached to both ends of a rear axle secured to the body of the baby carriage in such a manner that the rear wheels can be rotated about the axes thereof but cannot be swung rightward and leftward to steer the baby carriage.
When the direction of movement of the baby carriage is to be changed while the carriage is being pushed, the push handle 7 of the carriage is moved rightward or leftward. As a result of the rightward or leftward movement of the push handle 7, the front wheels a of the baby carriage are swung in a direction reverse to that of the movement of the push handle, so that the baby carriage is steered. The efficiency of steering the carriage is thus greatly improved.
The wheel steering apparatus of the baby carriage is effective as far as the push handle 7 for moving the carriage is secured to the body thereof so that the hand-gripped upper portion of the handle is located at the rear of the body of the carriage over the rear wheels b, as shown in FIG. 8. However, two significant problems occur when the push handle 7 is secured to the body of the baby carriage so that the hand-gripped upper portion of the handle is located at the front of the carriage over the front wheels a to enable the operator of the carriage to face the baby sitting on the seat 3 of the carriage, as shown in FIG. 9.
First, when the direction of movement of the baby carriage is to be changed, the front wheels a, which are located at the rear with regard to the direction of movement of the carriage, are swung to turn the body of the carriage to change the direction of the movement thereof. In other words, the front wheels a located at the rear with regard to the direction of movement of the baby carriage are swung in a direction reverse to that in which the carriage is desired to be moved to change its direction of movement. However, since the front wheels a need to be swung rightward or leftward to change the direction of movement, the operation of the carriage for the change is not only unnatural but also the locus of movement of the carriage becomes a large arc centering on the rear wheel b located at the front with regard to the direction of the movement of the carriage. In other words, the baby carriage is required to perform a useless motion. Moreover, since the front wheels a located at the rear with regard to the direction of movement of the baby carriage can always be swung to steer the baby carriage, the front wheels are in an unstable state where they are likely to be swung rightward and leftward, thus causing the carriage to move unstably.
Secondly, to solve the problem of the front wheels a being in an unstable state, locking devices 81 provided in the swivel mechanisms 8 are put into action to render the front wheels incapable of being swung rightward and leftward. One way of changing the direction of the movement of the baby carriage when the locking device 81 are in action is to push the push handle 7 downward to raise the rear wheels b located at the front with regard to the direction of movement of the baby carriage, and thereafter turn the body of the carriage about the front wheels a located at the rear with regard to the direction of movement of the carriage. Another way of changing the direction of the movement of the baby carriage when the locking devices 8 are in action is to lift the push handle 7 to raise the front wheels a located at the rear with regard to the direction of movement of the carriage and to thereafter turn the body of the carriage about the rear wheels b located at the front with regard to the direction of movement of the carriage. In each of the ways, however, a strong force for lifting the body of the baby carriage is needed. Therefore, it is not easy to operate the baby carriage in either of the above-mentioned ways.
To solve these two problems, a baby carriage having front and rear wheels in the form of swivel casters has been proposed. However, that baby carriage too has problems, as will now be described.
The carriage has swivel mechanisms 8 attached to the lower ends of legs as shown in FIG. 10. Two wheels a are provided at the two sides of each swivel mechanism 8 so that one of the wheels is located in an inner position under the body of the carriage. If a bag or basket for storing a purchased article, luggage or the like is hung from the bottom of the seat of the carriage, the rear wheels in the inner positions at both sides of the bag or basket limit the size thereof. Moreover, since the front and the rear wheels must be constructed to serve as swivel casters, the cost of the baby carriage is increased.